1. Field of the Invention
The invention relates to wireless monitoring of laboratory animals. In some aspects, the invention relates to detection and evaluation of paw guarding.
2. Description of the Related Art
In the discovery of neurological drugs, e.g., analgesics, many animal pain models are used. Most animal models used to screen for novel analgesics are based on monitoring the animal's response to evoked pain, often following an injury or insult. A typical example is the CFA model where a complete Freund's adjuvant (CFA) is injected into the rear paw of a rat to cause inflammation (i.e., injury). A stylus fitted with a strain gauge is then used to poke the injured paw and the force at which the animal withdraws its paw is taken as a measure of pain (i.e., evoked pain). Evoked pain models suffer from at least three disadvantages. First, the experiment is tedious as a lab technician has to wait for the animal to settle down before the stimulus can be reliably applied. Second, objectivity cannot be guaranteed. Even under blinded conditions, the temptation for a technician to bias results is always present. Lastly, pain evoked by an external stimulus is not representative of what humans typically feel when they are in pain. Indeed, human pain is mostly non-evoked: subsequent to injuries, humans continuously feel pain without any external stimulus (spontaneous pain).
Thus, there is a need for a spontaneous pain model and the corresponding animal pain detectors.